1. Field of the Invention
This invention relates to a system for detecting the position of an object having predetermined design features in a plane relative to a manipulator provided with ultrasonic sensors consisting of ultrasonic transmitters and ultrasonic receivers.
This invention relates also to a lifting and tipping mechanism for use on a garbage-collecting truck, which mechanism comprises a lifting arm, which carries a coupling device for cooperation with a mating coupling device mounted on a garbage bin.
2. Description of the Prior Art
When it is desired to automatically align a manipulator, which may consist, for example, of a gripper or coupling device, relative to an object that is to be gripped or manipulated, the position of the manipulator relative to the object in two planes crossing preferably at right angles must be detected so that the drive means for moving the manipulator can properly be actuated under the control of a preferably electronic controller in dependence on the coordinates which have been detected.
Video-optical sensors may be used as sensors for determining the position of two objects relative to each other but due to their high costs their use is highly restricted because they depend on illuminating conditions, color contrasts and positions to be detected. Such video-optical sensors are also highly delicate and may be damaged when used under rough operating conditions, such as with garbage bins in the collection of garbage. Moreover, it is also very difficult to obtain the required distance information by means of video-optical sensors.
Ultrasonic sensors consisting of ultrasonic transmitters and ultrasonic receivers are less liable to be deranged and more suitable for rough handling. But ultrasonic sensors which are presently known can only measure a distance between the sensor and a plane surface, although an aligning adjustment in lateral and vertical directions is also necessary when a manipulator is to be used to detect the position of an object to be handled and, subsequently, to grip that object.
The handling of a device for coupling a manipulator to an object will greatly be facilitated if an alignment is effected by an automatic adjustment in one plane so that, for example when it is desired to couple the object to the manipulator it will be sufficient subsequently to perform a preferably straight movement in a plane. Such movement can easily be controlled by hand.
Various lifting and tipping mechanisms of the kind described hereinbefore are known. For collection of garbage by garbage-collecting trucks provided with such mechanisms, the garbage-collecting workers place the garbage bin onto the coupling device so that the bins can be coupled and can be lifted and tipped when the garbage bins have been locked to the coupling device.
Published German application 34 20 058, which is not a prior publication, discloses a lifting and tipping mechanism which comprises at least one lifting arm that is pivotally movable about a transverse axis of a pouring unit or of the chassis of the truck and which at its free end carries a base rail, disposed parallel to the transverse axis and is pivotally movable between a receiving position, in which the rail is disposed genally below and in front of the driver's cab, and a pouring position in which the rail is disposed above and behind the drivers cab. The lifting arm is provided with extensible or pivoted means for a gripping of or for a coupling to a garbage bin. If the driver of a garbage-collecting truck provided with such lifting and tipping mechanism has sufficient experience and skill, he can move the truck close to a garbage bin and can couple the lifting and tipping mechanism to the garbage bin and can then lift, empty and return the garbage bin to rest. However, although the driver's cab and the driver's seat are so arranged that the driver can clearly view the coupling region, it is most difficult to control the coupling claw of the lifting arm in the region in which the coupling to the garbage bin is to be effected.